Photovoltaic or solar cells are designed for converting the solar radiation to electrical current. In concentrator solar photovoltaic applications the incoming sun light is optically concentrated before it is directed to solar cells. For example, the incoming sun light is received by a primary mirror that reflects the received radiation toward a secondary mirror that, in turn, reflects the radiation toward a solar cell, which converts the concentrated radiation to electrical current by the generation of electron-hole pairs in III-V semiconductor or single crystal silicon, for example.
The solar cell comprises a semiconductor integrated circuit die and therefore requires some manner of integrated circuit package or solar cell assembly, wherein the solar cell is connected to one or more functional devices. The solar cell assembly (SCA) may particularly provide environmental protection, heat dissipation and electrical connectivity to the solar cell.
In the art, SCAs are manufactured on a continuous single substrate base or comprise multiple components that are electrically isolated from each other. A critical issue is the back side contacting of the solar cell with the substrate of the SCA. Conventionally, a continuous single substrate functioning as a cooling substrate is contacted to the back side of a solar cell by means of selective noble metal (e.g., gold) deposition that represents a tedious and time-consuming, as well as expensive processing step.
In relation to the solar cell a big cooling area is needed, what stands in contrast to a fast and therefore cheap processing of the substrate. The provision of a number of electrically isolating material elements results in poor thermal conductivity and, thus, an inefficient overall thermal connection of the solar cell. Moreover, provision of materials of different material characteristics implies higher expenses and a plurality of connection regions and, therefore, may result in a significant deterioration of the (long-life) reliability of the manufactured SCA due to galvanic elements or thermo-mechanic stress.
Thus, despite the recent engineering progress there is still a need for providing an SCA that shows reliable electric contacting, efficient thermal conductivity and resistance against aging without increasing costs and, moreover, taking into account production rationalization.